How to connect an RCA preamp to a subwoofer

June 21, 2021
 by Paul McGowan

11 comments on “How to connect an RCA preamp to a subwoofer”

  1. Guilty as charged! I have for some time utilized the XLR ‘link’ connectors on the backs of my monoblocks to ‘daisy-chain’ the subwoofers. After hearing Paul’s advice, I’ll try the (XLR) Y-cable alternative to directly split the DAC output (I don’t use a pre-amp) between the monos and subbies and see if I can hear a difference. 😉

    Paul did advise me some years ago to do it that way but I ended up going the daisy-chain route and I couldn’t hear a difference. Time to retry it I think but this time I’ll give the recabling some more time to settle in. 🙂

    1. Good afternoon Brian!
      You can do that, but you’re gonna run in to a problem.
      And here is the problem that you’ll run in to.
      The line outs, are usually fixed.
      And because of the fact that they’re fixed, you won’t be able to control them with your volume control knob or whatever you’re using to control the volume of your stereo.
      I don’t know if they make these anymore.
      But Pioneer yoost to make recording levelers.
      After 41 long years, I still have mine.
      And It still works too!
      If you had one of those, then using that to hook your subwoofers up to your system, wouldn’t be a problem at all.
      But just to give you some what of an idea of how recording levelers work, they work this way.
      They were really designed to be used with tape recorders, that don’t have recording levelers built in to them.
      They only had fixed levels.
      Sometimes, they were below where the user or users wanted them to be.
      So this was Pioneer’s way, of solving that problem.
      But the box itself, is a preamp anyway.
      It went in between your stereo receiver and tape recorder.
      But as I said above, you can use it to control your subwoofers.

      1. John Price,
        You’re not supposed to control your subwoofers
        with the gain control of your amplifier.
        Subwoofers are not supposed to be an add-on bass
        gain facility; they are there to handle the sub-bass.
        You’re supposed to set your subwoofer(s) at the
        correct gain for the room & leave it there…ask any audiophile.
        You are typing more rubbish again (still)…PLEASE stop giving ridiculous ‘advice’.

        1. Turn around, and take a good look at yourself in a Mira.
          You are the one that posts trash.
          I don’t care what you say, but I do know, that it works.
          Because when subwoofers became popular in the early to mid nineties, I used my recording leveler that way to control my whole speaker system.
          I didn’t see or hear any problems.
          If you read Brian’s post carefully, you will see that he was asking if he could use the line outs part of the tape loop of his preamp to drive his powered subs.
          I told him what kind of issues and or problems he would be running in to by doing that.
          So I am telling you to your face right now, SHUT UP!

  2. Hi everybody
    Doesn’t using a Y split effectively halve the signal strength – voltage?
    Do you think this is a problem as now this mean that the amp and sub have to work harder to achieve the same level as if it were not split?

    1. MarcusG,
      I used RCA splitters to run a pair of System Audio – ‘SAXO 10’ subwoofers
      & I had no problem with attaining maximum gain on both of them.
      So, no; splitters should not cause a lack of signal to your subwoofers.

    2. Marcus, as I understand it, a properly wired splitter wires in ‘parallel’ rather than in ‘series’. From an electrical point of view this means that the voltage is unchanged but the current is ‘split’. However, being at the pre-amp stage, you’re only concerned about voltage. It’s at the power amp for your main speakers and the amp that powers your active sub-woofer where both voltage and current is ‘amplified’.

  3. I couldn’t get my head around using y-splitters for xlr’s to the sub’s as then I would be introducing a potentially crappy splitter (I’ve searched high and low for a high-end splitter) into the path of the amp’s and the sub.
    If I use high end XLR’s why would I want to put a $50 splitter in the signal path…?

    My thought was to get a second pair of pricey XLR’s to daisy chain the amps on the xlr out of the sub. . Yes more expensive but I’ve been sleeping at night.

    1. Paul hasn’t found that splitters or adapters cause sound degradation or any audible difference. I have once or twice while comparing adapters, although not in my main system, only in my computer one. Morrow Audio makes a good quality Y cord, if preferred over a cheap adapter, such as Paul mentioned.

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